A typical cotton picker includes a plurality of rotating barbed spindles which project into the plants. A picker drum assembly includes a plurality of vertical picker bars which each support a column of rotatable picker spindles. Each spindle is elongated and includes a drive gear which is driven to rotate the spindle about its principle axis as the barbs engage the cotton. The cotton wraps around the spindles and is doffed therefrom by a doffing mechanism which includes a plurality of flexible doffers, one for each row of picking spindles. Cotton pickers typically include from two to six forwardly located row units, each unit supporting a pair of upright picker drums having from twelve to sixteen picker bars. Each picker bar, in turn, rotatably supports up to twenty picker spindles. Several hundred spindles are therefore supported from each drum, and a large amount of mass is put in motion when the picker drums are rotated. The rotational speed of the spindles is on the order of 4000 rpm, and therefore the gyroscopic effect is substantial and adds to the forces generated by the system. The row units are relatively heavy and their weight shifts the center of gravity of the harvester forwardly. The weight of the spindles increases forces on drives and cam tracks.
A typical cotton picker spindle has a generally solid body fabricated from special heat-treated steel which is chrome plated to provide a hard, smooth surface. Such spindles have a high density and add a substantial amount of weight to the driven portion of the row unit. The drive speed of the picker drum assembly and thus machine productivity is limited by the amount of mass in motion.
A lubrication path directs grease through the picker bar to lubricate the bevel drive gears and the journal areas of the spindles. The picker bars must be greased at regular intervals to maintain adequate lubrication at the spindle journals. If the lubrication interval is too long, the spindle bearings do not receive adequate grease and will suffer premature wear and failure. Most spindle mounting nut assemblies are unsealed, so grease tends to leak out from the spindles, especially when the picker bars are over-greased to assure adequate spindle lubrication. The outward movement of grease flushes dust from the assembly to reduce contaminants in the picker bar. If the intervals between greasing are too long, dirt is inadequately flushed and wear is increased.
U.S. Pat. No. 4,757,671 discloses a seal assembly for reducing the amount of grease lost by the spindle assembly area and reducing the amount of contaminants entering the drive and journal areas. A first sealing ring contacts and seals the outer surface of the spindle. A second sealing ring, mounted over the first ring, seals non-moving components. Although the seal assembly reduces contaminants and the amount of lost lubricant, the seals tend to add substantial drag and significantly increase the power required to drive the large number of spindles on each drum. Previously, the amount of added power required by the seal assembly was high enough to make the seal assembly impractical.